Algae likely to linger, but there is hope for reservoir
Although Marion Reservoir’s toxic algae status was downgraded Friday from a warning to a less severe advisory, the lake’s shallowness and proximity to farmland mean the problem may never go away.
Still, an expert who has been studying the lake since 2007 thinks there may be ways to reduce algae growth and dangers posed to humans and animals.
According to Philip Barnes, assistant professor of biological and agricultural engineering at Kansas State University, the reservoir is among the most commonly warned bodies of water in the state because it provides an almost perfect environment for algae.
Farm runoff, high in nitrogen and phosphorous, creates nutrient-rich sediment where blue-green algae (actually are bacteria) can thrive.
Because the reservoir is relatively shallow, Barnes said, the water remains warm, and when there is little movement of water, it separates into layers.
“We have found that the layer just before the bottom contains no oxygen,” he said. “This changes the pH (acidity) and releases phosphorous — which, combined with the sunlight, creates the perfect environment for the bacteria to grow.”
Barnes and his students are working on solutions.
“Among the things we’re looking at are special pumps that stir the water to keep it from becoming stagnant,” he said. “These would be placed near where drinking water is gathered to keep the algae out and cut down on treatment costs.”
After the reservoir’s first prolonged algae warnings 10 years ago, both Marion and Hillsboro, which draw drinking water from the reservoir, invested in most costly treatment processes after briefly having to warn residents not to drink algae-tainted water.
Peggy Blackman, coordinator for Watershed Restoration and Protection Strategy at the reservoir, is looking to get cities that receive drinking water from the reservoir to help pay for pumps and Solar B aeration units. She will meet with them Sept. 9.
Solar B units are giant water filters that would add oxygen to the water much like a typical fish filter does.
Treating the whole reservoir would be prohibitively expensive, Barnes said, but he and his students are working on other ways to lessen algae’s impact. One could be as simple as giving the lake a stress-reducing massage, much like recent rains.
“We’re looking at a device that can be attached to the front of a boat that vibrates at different frequencies,” he said. “That device is in the trial stage, but we’ve had good results with it in the lab, and all someone would have to do is drive a boat back and forth across the water.”
Chemical solutions might be available, too, but they might be prohibitively expensive.
“With over 6,000 bodies of water in the state, we need something that people can actually afford to use, even on small livestock ponds,” Barnes said.
The reservoir’s downgraded status means the lake was reopened Friday to boating and swimming, although health officials still cautioned against drinking or directly contacting untreated lake water.
Experts disagree on the exact toll blue-green algae, technically known as cyanobacteria, has taken on humans. The World Health Organization and some global researchers have attributed human deaths to cyanobacteria. In the United States, however, only deaths of dogs and cattle have been universally accepted as linked to blue-green algae.
“The cattle dying was a realizations that the warnings are needed and larger animals can get sick and/or die from ingesting or absorbing the toxins released from the bacteria,” he said. “When the warning signs are put up, it means the algae levels are high enough we believe people could get sick from absorbing the water. By that time, they are way past the levels safe for pets.”
Reservoir clerk Torey Hett said two dogs became sick and died because of cyanobacteria at the reservoir.
“It’s a very serious problem we need to look at, and the people who are looking at it are sure they can find a solution in the future,” Hett said. “They, however, don’t think they will be able to start implementing that solution anytime soon.”
Funding for Barnes research has been suspended by Marion County because of billing issues.
“It’s a real shame, because without the funding to get the data I can’t show we need the grants to get more funding,” Blackman said.